英语问问1.He weighted about four kilograms when he was born.2.A

英语问问
1.He weighted about four kilograms when he was born.
2.A baby panda weighs 100 grams at birth .
为什么第一句用weighted(用ht)而第二句用weighs(用h)
It's a good idea to leave a message on her desk.
为什么不用to take而用to leave
We will visit the Great Wall if it is not rainy tomorrow.
为什么不用rain
You should not spend too much time playing computer games.
为什么这里time不可数,而have a great time的time 是可数的